Cement-burning furnace.



PATENTED JAN. 14, 1908 W. B. SNYDER. CEMENT BURNING FURNACE.

3 SHEETS-SHEET 1.

APPLIOATION FILED MAR.11, 1907.

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PATENTED JAN. L4; 1908.

WE. SNYDER. CEMENT BURNING FURNACE.

APPLICATION FILED MAR. 11, 1907.

3 SHEETS-SHEET 2.

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i 1||a|{ am 5 z a r/N flxb my m w vi w/ No. 876,602. PATENTED JAN.14,1908.

W. E. SNYDER.

CEMENT BURNING FURNACE.

APPLIGATION FILED MAR.11, 1907.

3 SHEETS-SHEET 3.

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UNITED s rn rns a'rnnr anion.

WILLOUGHBY ELWOOD SNYDER, OF NAZ ARETH, PENNSYLVANIA.

CEMENT-BURNING FURNACE.

Specification of Letters Patent.

Patented'Jan. 14, 1908..

Application filed March 11 1907- Serial No- 361.640.

Cement-Burning Furnaces, of which the following is a specification.

My invention relates to furnaces designed primarily for the calcinationof cement and generally for the treatment at high temper- 5 atures ofanv cognate materials.

My object is to provide a furnace for the above purposes, whereinelectricity constitutes the heat generative agent, and which.

shall be durable and economical in construc- These results I accomplishby the means herein described and shown in the accompanying drawings, in

Figure 1 is a view of the furnace in vertical section, omitting the feedand draftcompelling devices, and showing the rotary hearth with themeans for actuating the same, the stationary hood, the arc-electrodes,the electro-magnets and the means for raising and lowering the hearthrelatively to the arc-electrodes. Fig. 2 is a view of therfurnace inplan, showing the rotary hearth with its supporting spider, the hood,the arc-electrodes, the electro-magnets, the feed pipe,

thc stock or draft-compelling means, the

scraper and the apron therefor. Fig. 3 is a detail view in sideelevation, partly in vertical section and partly in perspective, of thehearth and hood at the point of charge and discharge, showing the feedpipe, the

stack, the scraper and the apron. Fig. 4 IS a detail-view in crosssection, of the hearth showing the scraper and the apron. Fig. 5

v is a detail view, in plan, of the means for estabhshing electricalconnection between the ment of the electro-magnets.

electro magnets and the power shaft, as shown in Fig. 1. Fig. 6 is adetail view, in elevation, showing. an alternative arrange- Fig. 7 is adetail view, in. elevation, of the shutter or slide at the charging endof the hood, showing the means for raising and lowering the shutter.

In Fig. 1 the spider or spoked wheel 1 car ries the annular reservoir 2from the bottom of which rises the vertical support 3 carrying thecontinuous annular hearth 4 with its top 5 composed of firc-briclr orother suitable heat-resisting material. The vertical sup- 6 and itsplates 9 are continuous save at the point of charge and discharge shownin Fig. 2 and hereinafter described; and the space included by the hoodabove the hearth should be such as to produce the necessaryreverberatory action of the heat of the arcs, hereinafter described,located within the hood above the hearth against the charge thereon.

At intervals in the hood 6 openings in the opposite sides thereof areformed, as shown in Figs. 1 and 2, for the introduction of aresupportingelectrodes or carbons, the positive carbons being indicated by thenumeral 10 and the negative by the numeral 11. The positive and negativecarbons are arranged in sets respectively, as shown in Fig.2, and arestaggered in such wise as to lay an arc across the entire width of thehearth. Each set of positive electrodes is provided with any,suit ablemechanism (not shown) for automatically advancing or feeding the carbonsto preserve an arc of the requisite constancy of energy. For thispurpose the mechanism. shown and described in Letters Patent No.816,753, dated April 3, 1906, granted to me for cement burning furnacemay be employed.

The hearth 4 with its spider 1 is rotated by the vertical shaft 12mounted in the bearing .13 in the frame 8 and upon the shoulder on thebearing 14 of the threaded sleeve hereinafter described. The pulleywheel 16 indicatcs any suitable means for rotating the shaft, spider andhearth.

Upon the hood 6 are located the electromagnets 17. These communicatewith the shaft 12, Fig. 1, by means of the arms 29, one end of each armbeing secured to an electromagnet and the other end being secured to thesplit ring 30 surrounding the shaft 12. Electrical connection with theshaft 12 is secured by the brushes 31 carried by the ring 30, as shownin plan in Fig. 5; Thus, refer-- ring to Fig. 1, the magnetic fluxpasses from the electro-ma-gnets l7 downward through the hood andhearth, is thence conducted llt through the arms of the spider or spokedwheel 1 to the shaft 12, ascends the shaft 12 to the brushes 31 andthence through the ring 30 and arms 29 back to the electro-magnets 17;The course of the current is indicated by the dotted arrows in Fig. 1.The function of the pairs of electromagnets above described is tointensif the calcining action of the arcsgenerate between the carbonpoints hereinabove described.

The means for feeding the cement or other material upon the hearth areindicated in Fig. 2 and shown in detail in Fig. 3. It consists of thefeed pipe 20 opening directly upon the hearth at thecharging end of thehood, the casing 21 forming the lower end of a suitable bin or hoppercontaining the material to be calcined, and the notched feed cylinder 22adapted to rotate in the casing 21. By the rotation of the feed cylinder22,by any suit: able mechanism (not shown) an'intermittent feed of thematerial is obtained from the hopper and casing 21 into the upper end ofthe feed pipe 20 whence it is deposited upon the hearth. at the chargingend of the hood. An intermittent deposit upon the hearth of the materialto be calcined is desirable for the reason that a continuous charge ordeposit becoming vitrified into a more or less solid and continuous massmight tend to become blocked or jammed within the hood, particularly atthe exit or discharge end thereof where the vitrified or calcinedproduct is turnedoif the hearth by the scraper 23 hereinafter described.

In Fig. 2 the hood 6 is seen to be continuous save for th'e spacebetween its charging and discharge ends. In this space is arranged thescraper 23, disposed diagonally across the l-i'earth and secured eitherto the ends of the hood or to the straps supporting the same, as shownin Figs. 2 and 3. To prevent any portion of the calcined product fromdropping into the reservoir 2 at this point as it is scraped or divertedfrom the hearth the stationary apron 24 is secured either to the ends ofthe hood or otherwise supportedfiasshown in Fig. 4, the lip of the apronextending partly beneath the hearth in such wise that the calcinedproduct removed from the hearth by the action of the scraper isdischarged over the apron without danger of blocking up the reservoir.

In Figs. 2 and 3 the stack 25 represents any suitable draft-compellingmeans. It communicates with the hood near the charging or feed endthereof and is designed to be provided with a fan or blower (not shown)of any well known form to create an up-draft in the stack. The inlet orchargingend of the hood is closed by the shutter or slide 26 Fig. 7,which allows of an openin between its lower edge and the surface of t ehearth sufficient to permit the material fed thereon by the pipe 20 toenter the hood. The exit or discharge end of the hood is open. Thus theup-draft created in the stack 25 by the blower or fan causes a currentof air to be drawn in shaped compartments of the reservoir 2, Fig.

1, are partially filled with any suitable fluid, such as a heavy oil andthe plates 9 extending down from each side of the hood into said liquidrender the hood continuously air-tight save at the charging anddischarge ends thereof. Thus no air is drawn in under the edges of thehood to interfere with the circulation above described. This arrangementof parts serves the further urpose of conserving as far as possible thefieat within the hood.

In the use of my furnace for the calcination of cement or other cognatematerials it may become desirable or necessary to employ diflerentdegrees of heat for the treatment of different substances or ofdifferent grades of the same substance. cure by the means shown in Fig.l. The lower end of the vertical shaft 12 is provided with a threadedsleeve 26 set-screwed thereto and controlled by the wheel 27 mountedupon the bearing'28. By rotating the wheel 27 the shaft 12 may belowered, an opening in the base 15 being provided for the purpose. Thislowers the hearth, increasing the space between the charges thereon andthe carbon oints above and likewise increasing the volaction of theelectrodes from the moment it enters the charging end of the hood it maybe over-burned and the product thus may be deteriorated. By thearrangement shown in Fig. 2 the material entering the charging end ofthe hood is subjected to the reverberatory heat of the hood and heart'h,which is least'at the point of entrance and increases as the hearth withits charge approaches theiirst set of electrodes. The distance betweenthe first set of electrodes and each succeeding set progressivelydiminishes, thus increasing both the direct and reverberatory heat towhich the charge is sub'ected in its circulation through the hood romthe charging end to the discharge end.

This adjustment I scv in Fig. 6 I have indicated an alternative tutes animprovement thereon.

magnetic re-inforcement of the calcining action of the carbons. In thisarrangement the spider 1 carries the annular reservoir 2 and the hearth.4 with its fire-brick covering 5 Air tightness at the sides of the hood6 is secured by an extension of the sides thereof into the reservoir. Thdisposition of the carbons 10 and 11 is as 'hereinbefore described. Theelectro-magnet 17 is located, as before, above the hood and is providedwith the head 32 which projects downward through the top of the hood asshown. The bent arm 33 passes from the electro-magnet l7 outward,downward and upward to a point immediately below the hearth, providing ameans whereby a continuous circulation of the elec tro-magnetic currentmay be obtained for the purpose of re-inforcing the action of thecarbons, as hereinbefore described.

In Fig. 7 is shown a means for adjusting the shutter 26 at any desiredheight and thus partly closing the charging end of the hood. To one endof the arm 34, pivoted upon the support 35 is booked the chain 36attached to the top of the shutter, and the chain 37, one end of whichis secured to the top of the, hood, is hooked to the dther end of thearm.

Having thus set forth in detail the component parts of my invention Ishall now describe the principle of my furnace together with its mode ofoperation. To that end I shall repeat a portion of the matter containedin the specification of j Letters Patent No. 816,753, dated April 3,1906, granted to me for cement burning furnace, inasmuch as my presentinvention consti- In the first place, I avoid actual penetration of acharge or mass of cement mixture to be treated by the arcs or any partof the arcs, which may prevent the manufacture of a sound cement. Iemploy the heatderived only by radiation, deflection or reverberation ofthe arcs. The arcs must be located a sufficient distance above thehearth to accommodate upon the hearth a charge disposed below, but notbetween the electrodes that sustain the are, it being well understoodthat the heat of an arc is most intense and that the hi hest degree ofits intensity is located directly withinthe current of or between theelectrodes supporting the are, where, as has been specified, it is, ifnot too intense, at least too much concentrated for its successfulemployment in the manufacture of cement. It is the object of myinvention in part to employ such heat, free, as it is, from products ofcombustion deleterious to cement at its highest efficient intensity butwithoutits c etionable degree or manner of concentration above referredto. To that end, 10- eating a mass of cement mixture to be treated orcharged out of the line of penetr'ation by the arcs I provide'for thefull and complete calcination.

arcs is directed, deflected, and'concentrated in ellieient energyagainst the charge upon the hearth.

In order to provide for the continuous manufacture o cement upon ahooded hearth of annular form, it is necessary, in 7 view of the factthat the immediate product of calcination in the manufacture of cementis a clinker or vitrified mass, to deposit ceuient mixture in separatecharges upon the hearth, because when so deposited .they

clinker into detached portions or cakes which may, through thecontinuous rotationf of the hearth, be automatically swept therefrom oneby one by the scraper. Further, an

advantage is derived over a continuous charging feed, in securing to thecharge that perfect homogeneity of calcination which is essential to themanufacture of a sound cement. Finally, it is advantageous to thepractical application of heat over an extended charge or mass to becalcined in the mamlfacture of cement but more especially in theaiplication of successive heats to separate charges, not only to makeprovision for the application of an abundant supply of oxygen to thecl'iarge while it is undergoing calcination, but also with especialreference to the sev. eral stages which it undergoes between initial Toexplain more fully, the initial application of heat to a charge ofcement mixture besides expelling moisture liberates carbonic-acid gas inquantity. Consequently in order to promote combustion it is not onlynecessary to keep a constant supplyof oxygen at the point of combustion,but also to draw off the carbonic-acid gas and other impurities ordeleterious products generated by the combustion. If, therefore,suitable draft-compelling means he provided and properly applied in themanufacture, it will serve a double purpose, both of affording'a fresh.supply of oxygen and of removing injurious products of combustion.Consequently I provide, by means of the stack communieating with thecharging end of the hood, for the generation of a current of air inopposition to the direction of movement of the hearth. This providespure air to the final combustion and conducts the current by successivestages to the'point'of initial combustion, whence the dense fumesgenerated by such initial combustion are conducted off through thestack, without possibility of contamination of the finished product.

While the general principle of my furnace herein described is similar tothat of the furnace for which Letters Patent No. 816,753

were granted me on April 3, 1906, the means whereby that principle ispractically applied have been mproved in the following particulars, viz:the means for rendering the hood air-tight throughout its extent, saveat the charging and discharge ends thereof, the arrangement of thearc-electrodes in staggered sets-whereby the width of the hearth is moreeffectively covered by the arcs than can be done by the use of asi nglepair of arc electrodes in place of a staggereijl set.

What I claim as my invention and desire to secure by Letters Patentisv 1. In a cement-burning furnace the combination with a rotatoryannular hearth provided with a stationary reverberatory hood, of a setof arc-electrodes operatively disposed within the hood above the hearth,

the members of the set being'staggered so that the series of arcsproduced between said members covers the entire width of the hearth, anelectro-magnet located above said set of arc-electrodes, and means forsecuring a continuous current from said electro-magnet downward upon thehearth, substantially as described.

2. in a cement-lnlrningl'urnace the combination with a rotatory annularhearth, a stationary reverberatory hood inclosing the same, anddraft-compelling means adapted to produce a current of air in oppositionto the direction of movement of the hearth, of a set of arc-electrodesoperatively disposed within the hood above the hearth, the individualcarbons composing the set being staggered so as to produce a series ofarcs extending diagonally across the entire width of the hearth, anelectro magnet located above said set of arc-electrodes and means forsecuring a current from said electromagnet through the hearth, toconcentrate and increase the eifect of the arc-electrodes, substantiallyas described.

3. In a cement-burning furnace the combination with a rotatory hearthand reverberatory hood provided with draft-compelling means adapted toproduce a current of air within the hood in opposition to the directionof rotation of the hearth, of a set of arc-electrodes operatively disosed within the hood above the hearth, t e individual carbons composingthe set being staggered so as to produce a series of arcs covering theentire width of the hearth, substantially as described.

4. In a cement-burning furnace the combination with a rotatory hearthand reverberatory hood provided with draft-compelling means adapted toproduce a current of air within the hood in opposition to the directionof rotation of the hearth, of a series of sets of arc-electrodesoperatively disposed within the hood above the hearth, the carbonscomposing each set being staggered so as to produce a series of arcscovering the entire width of the hearth, the distance between each setof arc-electrodes progressively di- 'ity of sets of arc-electrodesoperative minishing from the charging end to the discharge end of thehood, substantially as described. I

5. In a cement-burning furnace the combination with a rotatory hearthand reverberatory hood provided with draftsco'mpelling means adapted toproduce a current of air within the hood in oppositionto the di rectionof rotation of the hearth, of a series of sets of arc-electrodesoperatively disposed withinthe hood above the hearth, the carbonscomposing each set being staggered so as to produce a series of arcscoverin the entire width of the hearth, the interva .between each set ofarc-electrodes and the next progressively diminishing from the chargingend to the discharge end of the hood, and means i or verticallyadjusting the hearth rela.

ti'vely to the arc-electrodes, substantially as described.

6. In a cement-burning furnace the bination with a rotatory hearth andreverberatory hood provided with draft-compelling means adapted toproduce a current of air within the hood in opposition to the directionof rotation of the hearth, of a series of sets of arc-electrodesoperatively disposed within the hood above the hearth, the earbonscomposing each set being staggered to 7. In a cement-burning turnace'the combination with a rotatory hearth and reverberatory hood providedwithdraft-compelling means'adapted to produce a current of air withinthe hood in opposition to the direction of rotation of the hearth, of alugal- 1sposed within thehood above the heart the i carbons composingeach set being staggered to reduce a series of ares covering the entireuidth of the hearth, the interval between each set of arc-electrodes andthe next being progressively diminished from the charging end to thedischarge end of the hood, an electro-nia net located above each set ofarcelectror es, means, consisting of the threaded sleeve 26 and wheel27, for vertically adj usting the hearth relatively to thearc-electrodes, means, consisting of the reservoir 2 and plates 9, forrendering the hood substantially air-tight throughout its extent, ascraer, an apron, and means for intermittently ceding material upon thehearth, consisting of the as C0111- .20, substantially as escribed.

8. In a cement-burning furnace, a spider, an anndlar reservoir carriedthereby, an annular hearth mounted upon said reservoir, a non-rotaryreverberatory hood inclosing said hearth, the sides of said hoodextending downward into said reservoir, a plurality of sets ofarc-electrodes operatively disposed within the hood above the hearth,the carbons composing each set being staggered to produce a series ofarcs covering the entire width of the hearth and the interval betweeneach set of arc-electrodes and the next being progressively diminishedfrom the charging to the discharge end of the hood, a plurality ofelectro-magnets each of which is located upon the hood above itscorresponding set of arc-electrodes,means, consisting of the shaft 12and pulley 16, for rotating said spider, reservoir and hearth, means,consisting of the arms 29, ring and brushes 3], for securing a currentfrom said el'eetro-niagnets downward through the hearth, anddraft-compeb ling means adapted to produce a current of 3 air within thehood in opposition to the direc,

tion of rotation of the hearth,substantially as described.

9. In a cement-burning furnace, a rotatory wheel carrying an annularbifur'cate reservoir and a hearth, a non-rotary reverberatory hoodsuspended over and inclosing said hearth, the sides of said hoodextending sets of arc-electrodes operatively disposed within the hoodabove the hearth, the carbons of each set being staggered, anelcctro- IWILLOUGHBY ELWOOU SNYDER.

- W tnesses: I

" ,WiLsoN E. BECK,

l\"lATTIE M. W'ooumo.

downward into said reservoir, a plurality of magnet for each set ofarc-electrodes, dis posed upon the hood above the set of arc

